LoongArch: KVM: Implement handle iocsr exception

Implement kvm handle vcpu iocsr exception, setting the iocsr info into
vcpu_run and return to user space to handle it.

Reviewed-by: Bibo Mao <[email protected]>
Tested-by: Huacai Chen <[email protected]>
Signed-off-by: Tianrui Zhao <[email protected]>
Signed-off-by: Huacai Chen <[email protected]>

Author: zhaotianrui-loongson

arch/loongarch/include/asm/inst.h

@@ -65,6 +65,14 @@ enum reg2_op {
 	revbd_op	= 0x0f,
 	revh2w_op	= 0x10,
 	revhd_op	= 0x11,
+	iocsrrdb_op     = 0x19200,
+	iocsrrdh_op     = 0x19201,
+	iocsrrdw_op     = 0x19202,
+	iocsrrdd_op     = 0x19203,
+	iocsrwrb_op     = 0x19204,
+	iocsrwrh_op     = 0x19205,
+	iocsrwrw_op     = 0x19206,
+	iocsrwrd_op     = 0x19207,
 };
 
 enum reg2i5_op {
@@ -318,6 +326,13 @@ struct reg2bstrd_format {
 	unsigned int opcode : 10;
 };
 
+struct reg2csr_format {
+	unsigned int rd : 5;
+	unsigned int rj : 5;
+	unsigned int csr : 14;
+	unsigned int opcode : 8;
+};
+
 struct reg3_format {
 	unsigned int rd : 5;
 	unsigned int rj : 5;
@@ -346,6 +361,7 @@ union loongarch_instruction {
 	struct reg2i14_format	reg2i14_format;
 	struct reg2i16_format	reg2i16_format;
 	struct reg2bstrd_format	reg2bstrd_format;
+	struct reg2csr_format   reg2csr_format;
 	struct reg3_format	reg3_format;
 	struct reg3sa2_format	reg3sa2_format;
 };

arch/loongarch/kvm/exit.c

@@ -103,3 +103,94 @@ static int kvm_handle_csr(struct kvm_vcpu *vcpu, larch_inst inst)
 
 	return EMULATE_DONE;
 }
+
+int kvm_emu_iocsr(larch_inst inst, struct kvm_run *run, struct kvm_vcpu *vcpu)
+{
+	int ret;
+	unsigned long val;
+	u32 addr, rd, rj, opcode;
+
+	/*
+	 * Each IOCSR with different opcode
+	 */
+	rd = inst.reg2_format.rd;
+	rj = inst.reg2_format.rj;
+	opcode = inst.reg2_format.opcode;
+	addr = vcpu->arch.gprs[rj];
+	ret = EMULATE_DO_IOCSR;
+	run->iocsr_io.phys_addr = addr;
+	run->iocsr_io.is_write = 0;
+
+	/* LoongArch is Little endian */
+	switch (opcode) {
+	case iocsrrdb_op:
+		run->iocsr_io.len = 1;
+		break;
+	case iocsrrdh_op:
+		run->iocsr_io.len = 2;
+		break;
+	case iocsrrdw_op:
+		run->iocsr_io.len = 4;
+		break;
+	case iocsrrdd_op:
+		run->iocsr_io.len = 8;
+		break;
+	case iocsrwrb_op:
+		run->iocsr_io.len = 1;
+		run->iocsr_io.is_write = 1;
+		break;
+	case iocsrwrh_op:
+		run->iocsr_io.len = 2;
+		run->iocsr_io.is_write = 1;
+		break;
+	case iocsrwrw_op:
+		run->iocsr_io.len = 4;
+		run->iocsr_io.is_write = 1;
+		break;
+	case iocsrwrd_op:
+		run->iocsr_io.len = 8;
+		run->iocsr_io.is_write = 1;
+		break;
+	default:
+		ret = EMULATE_FAIL;
+		break;
+	}
+
+	if (ret == EMULATE_DO_IOCSR) {
+		if (run->iocsr_io.is_write) {
+			val = vcpu->arch.gprs[rd];
+			memcpy(run->iocsr_io.data, &val, run->iocsr_io.len);
+		}
+		vcpu->arch.io_gpr = rd;
+	}
+
+	return ret;
+}
+
+int kvm_complete_iocsr_read(struct kvm_vcpu *vcpu, struct kvm_run *run)
+{
+	enum emulation_result er = EMULATE_DONE;
+	unsigned long *gpr = &vcpu->arch.gprs[vcpu->arch.io_gpr];
+
+	switch (run->iocsr_io.len) {
+	case 1:
+		*gpr = *(s8 *)run->iocsr_io.data;
+		break;
+	case 2:
+		*gpr = *(s16 *)run->iocsr_io.data;
+		break;
+	case 4:
+		*gpr = *(s32 *)run->iocsr_io.data;
+		break;
+	case 8:
+		*gpr = *(s64 *)run->iocsr_io.data;
+		break;
+	default:
+		kvm_err("Bad IOCSR length: %d, addr is 0x%lx\n",
+				run->iocsr_io.len, vcpu->arch.badv);
+		er = EMULATE_FAIL;
+		break;
+	}
+
+	return er;
+}